The present invention is directed to retaining natural and synthetic fibers and other resilient material in bales, and it is intended to be especially useful in the cotton industry for maintaining cotton in bales of a desired shape and size, such as, for example, the widely used "Universal Density" bales.
Typically, a plurality of metal straps (called "bale ties") are looped around a bale of cotton at spaced-apart locations and the overlapping strap ends are secured to retain the bale at the desired density and shape. It is desirable that the bale ties, and the means for securing the overlapping ends of the bale ties, be able to accommodate efficient and safe application to the cotton bale and be capable of maintaining their integrity during the subsequent handling and transporation of the bale.
Proper design is especially important for bale ties used on higher density bales which necessarily have a higher degree of compression and therefore impose a greater amount of tension force in the bale ties. Also, the means for connecting the overlapping ends of each such high density bale tie must be able to withstand the tension forces imposed by the bale.
One conventional means for securing the overlapping ends of a bale tie employs a metal seal that is deformed about the overlapping ends of the metal strap comprising the bale tie. Examples of some types of metal seals used for cotton bale ties are disclosed in the U.S. Pat. No. 3,921,799 which is assigned to the assignee of the present invention.
One widely used type of metal seal has a generally C-shaped cross section. The seal has a crown portion and a pair of opposed side flanges or legs. The legs are adapted to be deformed about the overlapping end portions of the strap so as to cause the overlapping strap end portions to be held in surface-to-surface engagement between the seal crown and the seal legs.
Such a seal is applied to the overlapping end portions of the strap to prevent relative movement between the two overlapping strap end portions. The seal necessarily also prevents relative movement between the seal per se and both of the overlapping strap end portions. Such a seal must therefore be applied to the overlapping strap end portions in a manner that will effect sufficient engagement to withstand the tension forces imposed upon the strap by the outward pressure of the bale as well as to withstand the other forces that may be imposed upon the strap and/or seal as a result of handling, snagging, etc.
One conventional approach to applying such a seal includes notching or cutting into the seal as well as into the two overlapping strap end portions while displacing or offsetting portions of the strap relative to portions of the seal. This effects an engagement between the seal and the strap.
In an alternative approach, the seal is crimped but not notched or cut, whereby slipping or yielding can occur at the seal.
To ensure that the strap and seal on a bale do not break or become loose, the strap, the seal, and the engagement of the strap and seal must be designed to accommodate some selected maximum loading condition. It is difficult to select the maximum design strength of the assembled system of the strap and seal (in place on a bale) since the density to which the bale is compressed is not controlled by the designer of the strap and seal. Further, the designer of the strap and seal does not control the handling and storage of the strapped bale which may subject the bale to unexpectedly high impact or environmental loads.
As a result of these problems, the designer of a strap and seal system may attempt to "overdesign" the system to accommodate those very high continuous and/or transient loads which may affect only a relatively small percentage of the bales. Even with such overdesign, a bale in the field may be subjected to certain loading combinations which can cause failure of one or more of the straps and/or seals on the bale.
Accordingly, it would be desirable to provide a means for securing overlapping end portions of a bale tie or strap around a compressed bale so as to have the capability for accommodating overload conditions. Further, it would be desirable to provide an efficient and relatively simple method for so strapping a bale to accommodate such overload conditions.
It would also be advantageous to reduce, if not eliminate all together, the likelihood of catastrophic failure of the strap and/or seal. In some applications, it may also be beneficial to secure the seal to the strap without notching or cutting either the seal or the strap. This would avoid reduction of the cross section of the strap and of the seal and would eliminate sharp edges and corners which might otherwise snag or scratch adjacent surfaces during handling of the bale.